Flow machines



March 21, 1967 N. LAING 3,310,228

FLOW MACHINES Filed Feb. 17, 1966 2 Sheets-Sheet -1 INVENTQR NlkOlOUS Lolng ATTORNEYS March 21, 1967 N. LAING 3,310,228

FLOW MACHINES Filed Feb. 17, 1966 2 Sheets-Sheet 2 INVENTOR N il olous Loing M, M M, 9: 0%,,

ATTORNEYS United States Patent 3,310,228 FLOW MACHINES Nikolaus Laing, Hofener Weg 35, Aldingen, near Stuttgart, Germany Filed Feb. 17, 1966, Ser. No. 528,202 4 Claims. (Cl. 230125) This invention relates to flow machines and the application is a continuation-in-part of my copending application Ser. No. 450,749 filed Apr. 26, 1965, now abandoned, itself a continuation of my application No. 9,094 filed Feb. 16, 1960, now abandoned.

The invention more particularly concerns flow machines of the cross-flow type, that is, machines comprising a cylindrical bladed rotor mounted for rotation about its axis in a predetermined direction and defining an interior space, and guide means defining with the rotor a suction region and a pressure region, the guide means and rotor co-operating on rotation of the latter in said predetermined direction to induce a flow of fluid from the suction region through the path of the rotating blades of the rotor to said interior space and thence again through the path of said rotating blades to the pressure region. More especially but not exclusively, the invention concerns flow machines of the cross-flow type Wherein the guide means and rotor co-operate to set up a vortex of Rankine character having a core region eccentric of the rotor axis and a field region which guides the fluid so that flow through the rotor is strongly curved about the vortex core: such flow machines will herein be designated tangential machines.

The main object of the invention is to provide the guide means in the form of a simple, compact and easily manufactured unit so as to facilitate the construction and assembly of cross-flow machines incorporating such guide means, particularly small cross-flow fans.

The invention accordingly provides, in a cross-flow machine, a guide unit providing the guide means to cooperate with the rotor of such machine, and comprising a pair of end walls radially aligned with the end members of the rotor and having arcuate edges closely overlying the end members over a portion only of their circumference and at least one guide wall extending between the end walls and separating a discharge region of the machine from an entry region thereof.

It will generally be preferred to provide two spaced guide walls defining with the end Walls an outlet duct. The first wall will in this case preferably subtend a small angle at the rotor axis while the second wall will diverge steadily from the rotor, starting at the side of the rotor about opposite the first wall. At their lines of nearest approach to the rotor both walls are preferably well spaced therefrom, for example by at least half the radial blade depth.

The guide unit can advantageously be a one-piece plastics moulding, but can if required be built up from separate pieces secured together.

The invention will now be further described with reference to various embodiments thereof illustrated by Way of example With reference to the accompanying drawings wherein:

FIGURE I is a cross-sectional view of a cross-flow fan having a rotor and a guide unit according to the invention;

FIGURE 2 is a diagram showing how suction varies going around the periphery of the rotor;

FIGURE 3 is a perspective view of the rotor and guide unit illustrated in FIGURE 1;

FIGURE 3a illustrates in perspective a complete fan incorporating the parts shown in FIGURE 3 together with means for supporting such parts and driving the rotor;

FIGURE 4 is a longitudinal sectional view of a second complete fan having guide units according to the invention, and

FIGURE 5 is a cross-sectional view on the line VV in FIGURE 4 0f the fan shown therein.

Referring to FIGURES 1 to 3 of the drawing, the fan there shown comprises a bladed cylindrical rotor I having end discs 2, 3 aligned on the axis 4 and supporting between them a number of similar curved blades 5 extending parallel to the axis and arranged in a ring thereabout. The rotor -1 is mounted for rotation by means of a shaft 6 in the direction of the arrow 7; it will be seen that the blades are forwardly curved. A guide unit It) co-operates with the rotor 1 and comprises a pair of plane parallel end walls 111, 12 radially aligned with the end discs 2, 3 of the rotor, and having arcuate edges 13, 14 which closely overlie the edges of the end discs over about half their circumference. First and second guide walls 15, 16 extend between the end walls 11, 12 and define therewith a duct 17 leading to an out-let 18. The first guide wall 15 subtends an angle of some 20 at the rotor axis and converges with the rotor 1 in the direction of rotor rotation to define a tapering gap '19. The second guide wall 16 is arcuate and diverges steadily from the rotor, going from a line 20 of nearest approach to the rotor which is diametrally opposite the line 21 of nearest approach to the rotor of the wall 15. Both lines of nearest approach 20, 21 are spaced from the rotor by over half the radial depth of the blades 5.

In operation, the rotor 1 and guide unit 10 co-operate to set up and stabilize a vortex of Rankine type having a core region V which is eccentric of the rotor axis and interpenetrates the path of the rotating blades of the rotor adjacent the first guide wall 15 and extends into to gap 19. By reason of the vortex air is caused to flow from the entry region E, which extends over the lower half of the rotor as seen in the figures, through the path of the rotating blades of the rotor to the interior thereof and thence again through the path of the rotating blades to the duct 17 and out through the outlet 18. The flow, as illustrated by the line F in FIGURE 1, is strongly curved about the vortex core region V and takes place in planes perpendicular to the rotor axis. The vortex flow here shown is more fully described in British patent specification 876,611.

FIGURE 2 illustrates the. distribution of suction around the periphery of the rotor 1, in polar co-ordinates. At any angular location, suction varies as the radial distance between the rotor periphery 25 and the envelope 26. The position of the vortex core region is shown at V. This is a region of low pressure the influence of which extends some distance around the periphery in both directions. Any substantial endwise flow into the region where the vortex core forms has of course a disturbing or destructive effect on the vortex and consequently on the rotor throughput, at all events with a rotor of small axial length. It has been found, surprisingly, that provided the gaps 27 between the rotor end discs 2, 3 and the edges 18, 14 of the guide unit end walls 11, 1 2 are kept reasonably small, the amount of air which flows through the gaps into the core region and around it has little disturbing influence on the vortex and the flow through the rotor. A working clearance such as readily can be had in quantity production is sufficient for satisfactory operation.

FIGUR E 3a illustrates how the rotor 1 and guide unit It can be supported. A base 30 mounts a housing 31 containing a motor (not shown). The motor has a horizontal shaft, corresponding to the shaft 6 of FIGURE 3, on which the rotor is overhung-mounted; at the cost of some disturbance of flow, the shaft could extend through the rotor and support both end discs 2, 3. The guide unit is carried by the motor housing 3 1 so as to be angularly movable about the rotor axis, being held by friction in adjusted position. This construction is admirably suited for a small cheap desk fan.

FIGURE 4 shows another form of complete fan incorporating the rotor 1 and guide unit of FIGURES 1 to 3. The shape of the walls 15, 16 of the guide unit, as seen in FIGURE 5, differs slightly from that of the corresponding walls shown in FIGURE 1. Here a base 41 carries a motor 42 by means of legs 43 and two rotors l are overhung-mounted on opposite ends of the horizontal shaft 44 of the motor. Each rotor 1 co-opera-tes with one guide unit 10. As above described, the guide units being joined by a member 45 interconnecting opposite end walls 11 and secure-d to the motor housing by a knurled screw 46.

The guide unit according to the invention can be modified by omitting one or other of the guide walls 11, 12, particularly if the fan is intended for free-blowing only. The guide Walls need not assume the form shown. The first guide wall in particular need not define a converging gap.

It will be seen that the guide ur it can be positioned in a complete fan, as shown in FIGURES 3a and 4, after the rotor has already been positioned and thus facilitates assembly: it is also readily manufactured, as by plastics moulding. The size of the unit is much less than that of the guide means hitherto proposed where end walls extend over the whole area of the rotor end discs.

I claim:

1. Machine of the cross-flow type for inducing movement of fluid, comprising a cylindrical bladed rotor, having a series of forwardly curved blades extending longitudinally of the axis between end members and arranged in a ring about the axis, a one piece guide unit cooperating with the rotor and comprising a pair of end walls aligned with the end members of the rotor and having arcuate edges adjacent said end members and extending over a portion only of their circumference and at least one guide wall interconnecting the ends walls and separating a discharge region from an entry region, the rotor and guide wall cooperating on rotation of the rotor to induce a flow of fluid from the entry region through the path of the rotating blades to the interior of the rotor and thence again through the path of the rotating blades to the discharge region; said end walls extending over less than 180 of the periphery of the rotor end members.

2. A machine as claimed in claim 1, wherein the guide unit has two guide walls interconnecting the end walls, one guide wall subtending a small angle at the rotor axis and the other guide wall diverging steadily from the rotor going in the direction of rotor rotation from a line of nearest approach substantially opposite said one guide wall.

3. A machine as claimed in claim 2, wherein said one guide wall subtends less than 20 at the rotor axis.

4. A machine as claimed in claim 3, wherein said one guide wall converges with the rotor from an outlet opening, going in the direction of rotor rotation.

References Cited by the Examiner UNITED STATES PATENTS Re. 25,365 4/1963 Eck 230-425 2,033,273 3/1936 Buck 230 2,258,284 10/1941 Findley 230l25 2,339,575 1/1944 Lee 230125 FOREIGN PATENTS 340,945 10/1959 Switzerland.

DONLEY I. STOCKING, Primary Examiner.

HENRY F. RA-D UAZO, Examiner. 

1. MACHINE OF THE CROSS-FLOW TYPE FOR INDUCING MOVEMENT OF FLUID, COMPRISING A CYLINDRICAL BLADED ROTOR, HAVING A SERIES OF FORWARDLY CURVED BLADES EXTENDING LONGITUDINALLY OF THE AXIS BETWEEN END MEMBERS AND ARRANGED IN A RING ABOUT THE AXIS, A ONE PIECE GUIDE UNIT COOPERATING WITH THE ROTOR AND COMPRISING A PAIR OF END WALLS ALIGNED WITH THE END MEMBERS OF THE ROTOR AND HAVING ARCUATE EDGES ADJACENT SAID END MEMBERS AND EXTENDING OVER A PORTION ONLY OF THEIR CIRCUMFERENCE AND AT LEAST ONE GUIDE WALL INTERCONNECTING THE ENDS WALLS AND SEPARATING A DISCHARGE REGION FROM AN ENTRY REGION, THE ROTOR AND GUIDE WALL COOPERATING ON ROTATION OF THE ROTOR TO INDUCE A FLOW OF FLUID FROM THE ENTRY REGION THROUGH THE PATH OF THE ROTATING BLADES TO THE INTERIOR OF THE ROTOR AND THENCE AGAIN THROUGH THE PATH OF THE ROTATING BLADES TO THE DISCHARGE REGION; SAID END WALLS EXTENDING OVER LESS THAN 180* OF THE PERIPHERY OF THE ROTOR END MEMBERS. 